The present invention relates to a bonding apparatus and a bonding method of devices for bonding electrodes or leads of devices on electrodes of a display panel.
A liquid crystal panel or the like is used as a display panel for a display in electronic appliances. The display panel is assembled by bonding electrodes of the devices, a which are drivers for driving the display panel, on the electrodes formed at plural marginal bonding positions of a display panel made of glass plate or the like. As for the devices, tape carrier packages (TCPs), manufactured by a tape automated bonding (TAB) method, are generally used. The TAB method is used to obtain or fabricate TCPs by forming leads or electrodes of conductive material on the surface of a film carrier, bonding the chips cut out from a wafer on the leads, and blanking the outer lead portions of the leads by a cutting apparatus. The film carrier is formed of an ultrathin synthetic resin film of polyimide or the like.
Various types of apparatus of for bonding the outer leads, which are electrodes, of TCPs on the electrodes of the display panel are proposed.
For example, in the bonding apparatus disclosed in Japanese Laid-open Pat. No. 3-217033, the TCP is sucked in vacuum by a mounting head, and is conveyed near the mounting position. Outer leads of a TSP and electrodes of a display panel are taken by a camera in a same viewing field, and the deviation of them is measured. This deviation is then corrected by moving a substrate stage, and the positions arc adjusted. Next, by the backup of a backup mechanism, the lower surface of the display panel is supported, and the mounting head descends so that the outer leads of the TCP are bonded to the display panel. After bonding, the backup mechanism is returned to the home position, and the substrate stage is moved, and bonding of the next TCP is repeated.
In the device used as the driver for display panel, flip chips are also used aside from the TCPs manufactured by the TAB method. A flip chip is manufactured by forming bumps (electrodes) on its circuit surface. Bumps are generally bonded to electrodes on the display panel through an anisotropic conductive film (ACF). In this case, first the ACF is bonded to the electrodes on the display panel, and bumps on the flip chip are accurately positioned on the electrodes formed in the marginal area of the display panel, and bonded.
Or after the ACF is adhered to the bump of the flip chip, the bump of the flip chip is accurately positioned to the electrode formed in the marginal area of the display panel, and is bonded.
Generally, the outer leads of TCP are very thin and their pitch is extremely narrow. To bond outer leads of such narrow pitch on the electrodes on the display panel, the outer leads must be accurately positioned. What is more important, since a multiplicity of TCPs must be bonded on the display panel, the bonding job must be done at high speed. That is, the bonding apparatus for bonding TCPs on the display panel is required to have high precision and high speed.
In the conventional bonding apparatus mentioned above, however, after determining the deviation of the display panel and the TCP, by taking them by a camera, in order to support the display panel by the backup mechanism, the backup mechanism is transferred, and the backup mechanism is thereby caused to contact the display panel to shift the position of the display panel, and as a result, a bonding of high precision is not realized. Besides, every time a device is bonded, the backup mechanism must be operated, and the bonding work is delayed.
Incidentally, the display panel is quadrangular, and TCPs are bonded in the marginal area, but the devices bonded to one side (longer side) and the devices bonded to the other side (shorter side) are different in variety. Therefore, a TCP bonding apparatus is desired to be capable of bonding two different types of TCPs to the display device for the efficiency of the work. It is also preferred that the bonding job be done continuously on plural sides. The same problems occur also when bonding flip chips.